The production of electrical and electronic circuit boards often requires the mounting of several multilead electrical components on each board. Usually, such mounting techniques involve manual insertion of the leads of the multilead components, one component at a time, in corresponding holes of a circuit board. Clearly, such techniques result in small throughput, are time consuming, and labor intensive. Moreover, with electrical component packages becoming smaller in size, and with the number of leads on each package substantially increasing to achieve higher packaging densities, the problem of operator fatigue becomes a major one.
Several attempts were made to avoid the foregoing hindrances of manual insertion of a multilead component by resorting to automation. In the area of automatically mounting a multilead component or an I.C. package on a printed wiring board (PWB), the emphasis has been on achieving a high degree of accuracy in the positioning of the component held by a robotic hand or an automatic manipulator with respect to the holes of the PWB. Such high accuracies and close tolerances in the design and control of the robotic hand result in a complex and expensive automatic apparatus for accurately positioning the leads or terminals of the component with respect to their corresponding holes. Such an automatic apparatus is capable of mounting or inserting only one multilead component at a time into the PWB. Furthermore, the foregoing strict hand positioning requirements do not and cannot compensate for any dimensional deviations existing between the outer housing of the component and its leads.
A technique for automatically mounting a multilead component on a board is described in U.S. patent application Ser. No. 382,263 filed on May 26, 1982 and assigned to the assignee herein. Such a technique comprises the steps of placing the multilead component on the board such that each one of its leads is proximate to its corresponding hole in the board, and vibrating the board to cause the leads to fall into the holes. This technique clearly overcomes the above-mentioned strict design requirements on the robotic hand, as well as the component dimensional deviations problem. Although this technique operates satisfactorily for its intended purpose, it is capable of mounting only one multilead component at a time on the board.